Gothic 2!! Morrowind is excellent (and you can get the three pack for ~US$20), System Shock, Fallout 2, Wizardry 8, Divine Divinity, Arx Fatalis.

If you like SNES RPGs and you're in the US (because old roms are legal to download in the US, per the Library of Congress), the link in my sig goes to some translated SNES roms that never made it to the US, but a couple are better than any Final Fantasy offering.